Creep Fatigue Crack Growth Rate

Data produced from the use of a proposed new ASTM International standard will be employed in the design of new, more efficient aircraft engines as well as for steam and gas turbines used in power generation.

The proposed new standard, WK21984, Test Method for Creep-Fatigue Crack Growth Rate Testing, is being developed by Subcommittee E08.06 on Crack Growth Behavior, part of ASTM International Committee E08 on Fatigue and Fracture.

“The primary impetus for the standard is the need for advanced power plants and aircraft engines that will be designed to operate at higher temperatures to boost energy conversion efficiencies,” say Ashok Saxena, Ph.D., dean, College of Engineering, University of Arkansas, and Bilal Dogan, Ph.D., senior project manager, EPRI. Both are members of E08.

Saxena notes that the maximum operating temperature of turbines depends on the ability of materials to resist sustained and cyclic loads at high temperatures, particularly metals used in critical structure components of engines.

“The lives of these components at high temperatures are determined by the creep-fatigue properties of the materials used in these applications,” says Saxena. The proposed standard will also be useful in extending the lives of existing engines through a more accurate creep-fatigue analysis, thus postponing the cost of large replacements.

All interested parties are invited to participate in the development and round robin testing of WK21984.